diff mbox series

[v2,02/13] dt-bindings: pinctrl: renesas: Document RZ/V2H(P) SoC

Message ID 20240423175900.702640-3-prabhakar.mahadev-lad.rj@bp.renesas.com
State New
Headers show
Series Add PFC support for Renesas RZ/V2H(P) SoC | expand

Commit Message

Lad, Prabhakar April 23, 2024, 5:58 p.m. UTC 
From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Add documentation for the pin controller found on the Renesas RZ/V2H(P)
(R9A09G057) SoC. The RZ/V2H PFC varies slightly compared to the RZ/G2L
family:
- Additional bits need to be set during pinmuxing.
- The GPIO pin count is different.

Hence, a SoC-specific compatible string, 'renesas,r9a09g057-pinctrl', is
added for the RZ/V2H(P) SoC.

Also, add the 'renesas,output-impedance' property. The drive strength
setting on RZ/V2H(P) depends on the different power rails coming out from
the PMIC (connected via I2C). These power rails (required for drive
strength) can be 1.2V, 1.8V, or 3.3V.

Pins are grouped into 4 groups:

Group 1: Impedance
- 150/75/38/25 ohms (at 3.3V)
- 130/65/33/22 ohms (at 1.8V)

Group 2: Impedance
- 50/40/33/25 ohms (at 1.8V)

Group 3: Impedance
- 150/75/37.5/25 ohms (at 3.3V)
- 130/65/33/22 ohms (at 1.8V)

Group 4: Impedance
- 110/55/30/20 ohms (at 1.8V)
- 150/75/38/25 ohms (at 1.2V)

The 'renesas,output-impedance' property, as documented, can be
[0, 1, 2, 3], indicating x1/x2/x3/x4 drive strength.

As power rail information may not be available very early in the boot
process, the 'renesas,output-impedance' property is added instead of
reusing the 'output-impedance-ohms' property.

Also, allow bias-disable, bias-pull-down and bias-pull-up properties
as these can be used to configure the pins.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
RFC->v2
- Renamed renesas-rzv2h,output-impedance -> renesas,output-impedance
- Updated values for renesas,output-impedance
- Added bias properties
---
 .../pinctrl/renesas,rzg2l-pinctrl.yaml        | 25 ++++++++++++++++---
 1 file changed, 21 insertions(+), 4 deletions(-)

Comments

Lad, Prabhakar April 25, 2024, 9:49 a.m. UTC | #1 
Hi Geert,

Thank you for the review.

On Wed, Apr 24, 2024 at 10:06 AM Geert Uytterhoeven
<geert@linux-m68k.org> wrote:
>
> Hi Prabhakar,
>
> Thanks for your patch!
>
> On Tue, Apr 23, 2024 at 7:59 PM Prabhakar <prabhakar.csengg@gmail.com> wrote:
> > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> >
> > Add documentation for the pin controller found on the Renesas RZ/V2H(P)
> > (R9A09G057) SoC. The RZ/V2H PFC varies slightly compared to the RZ/G2L
> > family:
> > - Additional bits need to be set during pinmuxing.
> > - The GPIO pin count is different.
> >
> > Hence, a SoC-specific compatible string, 'renesas,r9a09g057-pinctrl', is
> > added for the RZ/V2H(P) SoC.
> >
> > Also, add the 'renesas,output-impedance' property. The drive strength
> > setting on RZ/V2H(P) depends on the different power rails coming out from
> > the PMIC (connected via I2C). These power rails (required for drive
> > strength) can be 1.2V, 1.8V, or 3.3V.
> >
> > Pins are grouped into 4 groups:
> >
> > Group 1: Impedance
> > - 150/75/38/25 ohms (at 3.3V)
> > - 130/65/33/22 ohms (at 1.8V)
> >
> > Group 2: Impedance
> > - 50/40/33/25 ohms (at 1.8V)
> >
> > Group 3: Impedance
> > - 150/75/37.5/25 ohms (at 3.3V)
> > - 130/65/33/22 ohms (at 1.8V)
> >
> > Group 4: Impedance
> > - 110/55/30/20 ohms (at 1.8V)
> > - 150/75/38/25 ohms (at 1.2V)
> >
> > The 'renesas,output-impedance' property, as documented, can be
> > [0, 1, 2, 3], indicating x1/x2/x3/x4 drive strength.
>
> The documentation says "x1/x2/x4/x6" for all but Group 4 (P20/P21).
> Still, the actual values don't seem to match the magnification factors...
>
> > As power rail information may not be available very early in the boot
> > process, the 'renesas,output-impedance' property is added instead of
> > reusing the 'output-impedance-ohms' property.
> >
> > Also, allow bias-disable, bias-pull-down and bias-pull-up properties
> > as these can be used to configure the pins.
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
>
> > --- a/Documentation/devicetree/bindings/pinctrl/renesas,rzg2l-pinctrl.yaml
> > +++ b/Documentation/devicetree/bindings/pinctrl/renesas,rzg2l-pinctrl.yaml
> > @@ -111,6 +116,18 @@ additionalProperties:
> >          output-high: true
> >          output-low: true
> >          line-name: true
> > +        bias-disable: true
> > +        bias-pull-down: true
> > +        bias-pull-up: true
> > +        renesas,output-impedance:
> > +          description: |
> > +            Output impedance for pins on RZ/V2H(P) SoC.
> > +            0: Corresponds to x1
> > +            1: Corresponds to x2
> > +            2: Corresponds to x3
> > +            3: Corresponds to x4
>
> Hence I'd drop the multiplication factors, and just say the meaning
> of the value is pin-dependent?
>
Agreed, I will update the description "Output impedance for pins on
RZ/V2H(P) SoC. 0/1/2/3 corresponds to register bit values that can be
set in PFC_IOLH_mn register which adjusts the drive strength value and
is pin-dependent"

Cheers,
Prabhakar

> > +          $ref: /schemas/types.yaml#/definitions/uint32
> > +          enum: [0, 1, 2, 3]
> >
> >      - type: object
> >        additionalProperties:
>
> Gr{oetje,eeting}s,
>
>                         Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/pinctrl/renesas,rzg2l-pinctrl.yaml b/Documentation/devicetree/bindings/pinctrl/renesas,rzg2l-pinctrl.yaml
index 881e992adca3..089b3ce61bac 100644
--- a/Documentation/devicetree/bindings/pinctrl/renesas,rzg2l-pinctrl.yaml
+++ b/Documentation/devicetree/bindings/pinctrl/renesas,rzg2l-pinctrl.yaml
@@ -26,6 +26,7 @@  properties:
               - renesas,r9a07g043-pinctrl # RZ/G2UL{Type-1,Type-2} and RZ/Five
               - renesas,r9a07g044-pinctrl # RZ/G2{L,LC}
               - renesas,r9a08g045-pinctrl # RZ/G3S
+              - renesas,r9a09g057-pinctrl # RZ/V2H(P)
 
       - items:
           - enum:
@@ -66,10 +67,14 @@  properties:
     maxItems: 1
 
   resets:
-    items:
-      - description: GPIO_RSTN signal
-      - description: GPIO_PORT_RESETN signal
-      - description: GPIO_SPARE_RESETN signal
+    oneOf:
+      - items:
+          - description: GPIO_RSTN signal
+          - description: GPIO_PORT_RESETN signal
+          - description: GPIO_SPARE_RESETN signal
+      - items:
+          - description: PFC main reset
+          - description: Reset for the control register related to WDTUDFCA and WDTUDFFCM pins
 
 additionalProperties:
   anyOf:
@@ -111,6 +116,18 @@  additionalProperties:
         output-high: true
         output-low: true
         line-name: true
+        bias-disable: true
+        bias-pull-down: true
+        bias-pull-up: true
+        renesas,output-impedance:
+          description: |
+            Output impedance for pins on RZ/V2H(P) SoC.
+            0: Corresponds to x1
+            1: Corresponds to x2
+            2: Corresponds to x3
+            3: Corresponds to x4
+          $ref: /schemas/types.yaml#/definitions/uint32
+          enum: [0, 1, 2, 3]
 
     - type: object
       additionalProperties: